I have a customer who wants to set zfs_arc_max to 1G for a 16G system, and 2G for a 32G system. Both of these are SAP and/or Oracle db servers. They apparently want to maximize the amount of memory available for the applications.
My question, now, is whether it would be advisable to do this, and - if not - what the impact might be. The 32G system is an M3000; the 16G system is a V490. Both are running Solaris 10 Update 8, patched to 147440-09. I have a feeling that setting zfs_arc_max this low is not a good idea, but would like to get some corroborating information/references, if possible. Thanks Rick From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-boun...@opensolaris.org] On Behalf Of Richard Elling Sent: Thursday, May 17, 2012 11:24 AM To: Paul Kraus Cc: ZFS Discussions Subject: Re: [zfs-discuss] zfs_arc_max values On May 17, 2012, at 5:28 AM, Paul Kraus wrote: On Wed, May 16, 2012 at 3:35 PM, Paynter, Richard <richard.payn...@infocrossing.com> wrote: Does anyone know what the minimum value for zfs_arc_max should be set to? Does it depend on the amount of memory on the system, and - if so - is there a formula, or percentage, to use to determine what the minimum value is? I would assume that it should not be set any lower than `kstat zfs::arcstats:c_min`, which I assume you can set with zfs_arc_min in /etc/system, but that does not really answer your question. arc_c_max and arc_c_min are used for different things. If you make significant changes there, then it is a good idea to set both zfs_arc_min, zfs_arc_max, and zfs_arc_meta_limit as a set. NB, the minimum size of these is 64MB. -- richard -- ZFS Performance and Training richard.ell...@richardelling.com +1-760-896-4422 Confidentiality Note: This e-mail, including any attachment to it, may contain material that is confidential, proprietary, privileged and/or "Protected Health Information," within the meaning of the regulations under the Health Insurance Portability & Accountability Act as amended. If it is not clear that you are the intended recipient, you are hereby notified that you have received this transmittal in error, and any review, dissemination, distribution or copying of this e-mail, including any attachment to it, is strictly prohibited. If you have received this e-mail in error, please immediately return it to the sender and delete it from your system. Thank you.
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